New to Searchlight? Please start here.

Check pod-volume

Check command pod-volume is used to check percentage of available space in Kubernetes Pods.

Spec

pod-volume check command has the following variables:

• volumeName - Name of volume whose usage stats will be checked
• secretName - Name of Kubernetes Secret used to pass hostfacts auth info
• warning - Warning level value (usage percentage defaults to 80.0)
• critical - Critical level value (usage percentage defaults to 95.0)

Execution of this command can result in following states:

• OK
• Warning
• Critical
• Unknown

Tutorial

Before You Begin

At first, you need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using Minikube.

Now, install Searchlight operator in your cluster following the steps here. To use pod-volume command, please also install Hostfacts server in your cluster.

To keep things isolated, this tutorial uses a separate namespace called demo throughout this tutorial. Run the following command to prepare your cluster for this tutorial:

$ kubectl create namespace demo
namespace "demo" created

$ kubectl get namespaces
NAME          STATUS    AGE
default       Active    6h
kube-public   Active    6h
kube-system   Active    6h
demo          Active    4m

Check volume of pods with matching labels

In this tutorial, a PodAlert will be used check volume stats of pods with matching labels by setting spec.selector field.

$ cat ./docs/examples/pod-alerts/pod-volume/demo-0.yaml

apiVersion: monitoring.appscode.com/v1alpha1
kind: PodAlert
metadata:
  name: pod-volume-demo-0
  namespace: demo
spec:
  selector:
    matchLabels:
      app: nginx
  check: pod-volume
  vars:
    volumeName: www
    warning: '70'
    critical: '95'
  checkInterval: 5m
  alertInterval: 3m
  notifierSecretName: notifier-config
  receivers:
  - notifier: Mailgun
    state: Critical
    to: ["ops@example.com"]

$ kubectl apply -f ./docs/examples/pod-alerts/pod-volume/demo-1.yaml
persistentvolumeclaim "boxclaim" created
pod "busybox" created
podalert "pod-volume-demo-1" created

$ kubectl get pods -n demo
NAME      READY     STATUS    RESTARTS   AGE
web-0     1/1       Running   0          10m
web-1     1/1       Running   0          10m

$ kubectl describe podalert -n demo pod-volume-demo-0
Name:		pod-volume-demo-0
Namespace:	demo
Labels:		<none>
Events:
  FirstSeen	LastSeen	Count	From			SubObjectPath	Type		Reason		Message
  ---------	--------	-----	----			-------------	--------	------		-------
  11m		11m		1	Searchlight operator			Warning		BadNotifier	Bad notifier config for PodAlert: "pod-volume-demo-0". Reason: secrets "notifier-config" not found
  11m		11m		1	Searchlight operator			Normal		SuccessfulSync	Applied PodAlert: "pod-volume-demo-0"
  11m		11m		1	Searchlight operator			Normal		SuccessfulSync	Applied PodAlert: "pod-volume-demo-0"

Voila! pod-volume command has been synced to Icinga2. Please visit here to learn how to configure notifier secret. Now, open IcingaWeb2 in your browser. You should see a Icinga host demo@pod@minikube and Icinga service pod-volume-demo-0.

Check volume stats of a specific pod

In this tutorial, a PodAlert will be used check volume stats of a pod by name by setting spec.podName field.

$ cat ./docs/examples/pod-alerts/pod-volume/demo-1.yaml

apiVersion: monitoring.appscode.com/v1alpha1
kind: PodAlert
metadata:
  name: pod-volume-demo-1
  namespace: demo
spec:
  podName: busybox
  check: pod-volume
  vars:
    volumeName: mypd
    warning: '70'
    critical: '95'
  checkInterval: 5m
  alertInterval: 3m
  notifierSecretName: notifier-config
  receivers:
  - notifier: Mailgun
    state: Critical
    to: ["ops@example.com"]

$ kubectl apply -f ./docs/examples/pod-alerts/pod-volume/demo-1.yaml
persistentvolumeclaim "boxclaim" created
pod "busybox" created
podalert "pod-volume-demo-1" created

$ kubectl describe podalert -n demo pod-volume-demo-1
Name:		pod-volume-demo-1
Namespace:	demo
Labels:		<none>
Events:
  FirstSeen	LastSeen	Count	From			SubObjectPath	Type		Reason		Message
  ---------	--------	-----	----			-------------	--------	------		-------
  1m		1m		1	Searchlight operator			Warning		BadNotifier	Bad notifier config for PodAlert: "pod-volume-demo-1". Reason: secrets "notifier-config" not found
  1m		1m		1	Searchlight operator			Normal		SuccessfulSync	Applied PodAlert: "pod-volume-demo-1"
  1m		1m		1	Searchlight operator			Normal		SuccessfulSync	Applied PodAlert: "pod-volume-demo-1"

Pause Alert

To pause alert, edit PodAlert pod-volume-demo-1 to set spec.paused to be true

$ kubectl edit podalert pod-volume-demo-1 -n demo

spec:
  pause: true

Searchlight operator will delete Icinga Services for this alert. To resume, edit and set spec.paused to be false

Cleaning up

To cleanup the Kubernetes resources created by this tutorial, run:

$ kubectl delete ns demo

If you would like to uninstall Searchlight operator, please follow the steps here.

Next Steps

• To periodically run various checks on a Kubernetes cluster, use ClusterAlerts.
• To periodically run various checks on nodes in a Kubernetes cluster, use NodeAlerts.
• See the list of supported notifiers here.
• Wondering what features are coming next? Please visit here.
• Want to hack on Searchlight? Check our contribution guidelines.